Page 41 - IEAR1_60y_Book_of_Abstracts

60 Years of IEA-R1 International Workshop 31

CONCENTRATION AND DISTRIBUTION EVALUATIONS OF TRACE
AND RARE EARTH ELEMENT IN SAMPLE SEDIMENTS OF THE
BILLINGS AND GUARAPIRANGA RESERVOIR SYSTEMS P51

2
L.S. Silva a,1 , F.J. Ferreira and D.I.T. Fávaro 1
a larascroft@hotmail.com
1 Nuclear and Energy Research Institute, São Paulo, Brazil
2
Inorganic Chemistry Sector ELAI, São Paulo, Brazil

The Alto Tietê Water Resources Management Unit (UGRHI-6) of the São Paulo
Metropolitan Region (RMSP) is composed of 34 municipalities and covers the up-
per part of the Tietê River. Due to excessive urbanization of the region, its water
courses have lost their natural characteristics, resulting severe changes in water flow
and quality. The present study evaluated the concentration and distribution of trace
and rare earth elements in samples of surface sediment collected at strategic points
in the Billings System (including Rio Grande and Guarapiranga Reservoirs). In order
to determine the concentration of trace and rare earth elements (Ce, Eu, La, Lu,
Nd, Sm, Tb and Yb) in the sediments, instrumental neutron activation technique
(INAA) was used. Methodology validation was performed by the analysis of refer-
ence materials and Z score calculation. To evaluate the sources of anthropogenic
contamination the enrichment factor (FE) and the geoacumulation index (IGeo) were
calculated using NASC, UCC and Guarapiranga region soil Reference Values. The
results obtained were compared to the concentration guideline values established by
environmental agencies, such as the CCME (Canadian Council of Ministers of the
Environment) for As, Cr and Zn, as well as the values found in other published studies
carried out in the region. Most of the analyzed points exceeded TEL values and, in
some points, PEL values of, for these three elements, indicative of the poor quality
of the sediments in these reservoirs. In general terms, the elements As, Cr, Sb and
Zn through FE and IGeo calculations present enrichment at all points analyzed, in
both collection campaigns, with the exception of the Rio Grande reservoir points.
The region where the studied reservoirs are located receives untreated sewage as well
as pollution from the urban occupation and industrial and mining activities, making
it difficult to accurately identify the pollution sources of the reservoirs. The Billings
Reservoir also receives waters from the Tietê and Pinheiros Rivers on rainy days. This
study verified higher concentrations of the elements analyzed in the Billings Reser-
voir, indicating a greater contamination levels in relation to the other regions. This
study revealed the need for frequent monitoring of sediment quality in the Billings
and Guarapiranga Reservoirs as an important procedure for periodic evaluations of
the of the basin water quality, considering its importance in the water supply for the
Metropolitan Region of São Paulo.

This work was presented at International Nuclear Atlantic Conference – INAC 2017 (poster)